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How might Crail have looked 335 million years ago?

Introduction

Crail is a small fishing village located in south east Fife
(Scotland) and provides a fascinating insight into the Carboniferous
period 335 million years ago. What distinguishes Crail from the
surrounding localities is the occurrence of several well preserved
Arthropleura (giant centipede) trackways, which can be seen in situ in
the neighbouring bay. Please note, the trackways are scientifically
important and must not be collected or damaged, we ask that all visitors
respect this.

Left: View over
Crail harbour from the road leading into the village.
Right: A small coffee shop provides refreshments and views
over the bay.

Parking is available throughout the village and a small coffee
shop provides refreshments and stunning views across the bay. Access
to the beach is made alongside the western edge of the harbour (see
photo above-left), this leads into the first of several small bays
described below.

The geology of Crail

The rocks at Crail were formed within an expansive delta system
during the Carboniferous period (Visean stage / Holkerian sub-stage),
approximately 335 million years ago. Much of the rock exposed today was
formed by sands and silts carried and deposited by rivers across the
region. It's interesting to note that at this time the river system
flowed south west, completely opposite to the present situation; the
source of the rivers during this time was where the North Sea is today.

This period represents a great change in the earth's history,
with land plants evolving into large trees and ferns, and
amphibians, reptiles and giant flying insects inhabiting the humid
forests. One of the notable inhabitants of the forest floor was
Arthropleura, a giant centipede which evolved from crustacean-like
ancestors and was able to grow larger than modern Arthopods because
of the high percentage of oxygen in Earth's atmosphere at that time
and because of the lack of large terrestrial predators.

Where to look for fossils?

Fossils can be found among the pebbles and foreshore exposures
within each of the neighbouring bays west of the harbour. Heading along
the beach (at low tide) the first fossil you're likely to encounter is a
giant tree stump (see below-left); continuing further you'll shortly
reach the site of the Arthropleura tracks (see below-right).

Left: Giant tree
stump visible in the bottom-left of the photo. Right:
Horizontal bedding and location of the Arthropleura tracks.

There are several Arthropleura tracks, the most striking of which
is located above sea level in the cliff section shown above-right.
The first bay ends shortly after the tracks, beyond which several
more bays can be found and provide the best opportunity to collect
fossils.

As with all coastal locations, a fossil hunting trip is best timed to coincide
with a falling or low-tide. For a relatively low one-off cost we
recommend the use of Neptune Tides software, which provides
future tidal information around the UK. To download a free trial
click here.
Alternatively a free short range forecast covering the next 7 days
is available on the BBC website
click here.

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What fossils might you find?

Crail is most famous for the occurrence of Arthropleura
trackways in the cliffs and on the foreshore boulders; these
impressive giant centipedes measured up to 2 meters (over 6 feet) in
length and comprised of an armoured exoskeleton and dozens of
sharply pointed legs running along its underside.

A model Arthropleura
displayed in the Hunterian Museum in Glasgow.

The spacing of the tracks at Crail indicate this particular
specimen measured over 4 feet. The most impressive pair of tracks
occur above the foreshore (described above), each comprising two
clear uniform impressions of the creatures many feet. Given the
similarity of the two tracks and the unique circumstances that led
to their preservation, it's most probable that they were left by the
same creature within a short time of each other (possibly the same
day).

Left: A trace fossil -
two trackways left
in the sediment by an
Arthropleura giant 'centipede'
hi-res image. Right: A close-up of the tracks.

Important: Please respect the trackways and do not
damage or attempt to collect any part of them. We wish to remind
visitors that these are extremely rare and scientifically important
(in their life position).

During our recent visit we observed a further two separate
trackways, as shown below; these particular specimens are being
subjected to extensive weathering by the sea, the result of which is
apparent and a great shame. We hope that the addition of Crail to
the website may serve to amplify the efforts to preserve them.

Left: A second
Arthropleura trackway on a foreshore boulder.
Right: A third trackway.

As well as several trackways the first bay is also host to a range
of other fossils, in particular a large tree stump (below-right) and
ripple marks formed in the Carboniferous sediment (below-left).

Left: Ripple marks
on the surface of a large foreshore boulder. Right:
A large tree stump on the foreshore.

Hammering is not recommended in this area, as the vast majority of
finds are in situ and should be left for others to observe. Among
the foreshore boulders it's possible to collect small pebbles
containing evidence of trees and other vegetation present at the
time; the specimens below show two separate types of tree material.

Left: A fragment of
tree bark (Lepidodendron). Right: Another
fragment of tree bark.

The most common fossils along this stretch of coast are the trunk
and roots of Lepidodendron trees, which appear in situ of the
foreshore. The bark is identifiable by its characteristic
diamond-shaped leaf cushions, whereas the roots (known commonly as
Stigmaria) are covered by a series of small pits (see below-left),
from which smaller root appendages grew. Some Lepidodendron species
could grow up to 40 metres; the roots spread horizontally,
indicating humid environments.

Left:Stigmaria
(Lepidodendronroot). Right: A
large section of unidentified tree trunk.

Leaving the first bay and moving further along the foreshore, the
volume of beach pebbles increases and as does the opportunity to
collect fossils. If you're equipped with a hammer and chisel (see
equipment) you can find a variety of fossils within them. The photo
below-right shows a closeup of a split pebble, within which a small
bivalve shell can be seen alongside plant
debris. The presence of these two fossils indicates the environment
was densely vegetated and in immediate proximity to water.

Left: A split beach
pebble containing plant and shell remains. Right:
A close-up of the bivalve and vegetation.

Please note, the foreshore west of Crail is designated a Site of
Special Scientific Interest (SSSI), which makes it illegal to hammer
or remove any situ material.

Tools & equipment

It's a good idea to spend some time considering the tools and
equipment you're likely to require while fossil hunting at Crail. Preparation in advance will help ensure your visit is
productive and safe. Below are some of the items you should consider
carrying with you. You can purchase a selection of geological tools
and equipment online from
UKGE.

Hammer:
A strong hammer will be required to split prospective rocks. The
hammer should be as heavy as can be easily managed without causing
strain to the user. For individuals with less physical strength and
children (in particular) we recommend a head weight no more than
500g.

Chisel: A chisel is required in conjunction with a
hammer for removing fossils from the rock. In most instances a
large chisel should be used for completing the bulk of the work,
while a smaller, more precise chisel should be used for finer work.
A chisel founded from cold steel is recommended as this metal is
especially engineered for hard materials.

Safety glasses: While
hammering rocks there's a risk of injury from rock splinters
unless the necessary eye protection is worn. Safety glasses ensure any splinters are deflected away from the eyes. Eye
protection should also be worn by spectators as splinters can
travel several metres from their origin.

Strong bag: When considering the type of bag to use it's worth setting aside
one that will only be used for fossil hunting, rocks are usually
dusty or muddy and will
make a mess of anything they come in contact with. The bag will also
need to carry a range of accessories which need to
be easily accessible. Among the features recommended include: brightly coloured,
a strong holder construction, back
support, strong straps, plenty of easily accessible pockets and a rain cover.

Walking boots: A good pair of walking boots will
protect you from ankle sprains, provide more grip on
slippery surfaces and keep you dry in wet conditions. During your
fossil hunt you're likely to encounter a variety of terrains so
footwear needs to be designed for a range of conditions.

For more information and examples of tools and equipment
recommended for fossil hunting
click here
or shop online at
UKGE.

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FOSSILS

Protecting your finds

It's important to spend some time considering the best way to
protect your finds onsite, in transit, on display and in storage.
Prior to your visit, consider the equipment and accessories you're
likely to need, as these will differ depending on the type of rock,
terrain and prevailing weather conditions.

When you discover a fossil, examine the surrounding matrix (rock)
and consider how best to remove the specimen without breaking it;
patience and consideration are key. The aim of extraction is to
remove the specimen with some of the matrix attached, as this will
provide added protection during transit and future handling;
sometimes breaks are unavoidable, but with care you should be able
to extract most specimens intact. In the event of breakage,
carefully gather all the pieces together, as in most cases repairs
can be made at a later time.

Join us on a fossil hunt

Left: A birthday party with
a twist - fossil hunting at
Peacehaven.
Right: A family hold their prized ammonite at Beachy Head.

Discovering Fossils guided fossil hunts reveal evidence of life that
existed millions of years ago. Whether it's your first time fossil
hunting or you're looking to expand your subject knowledge, our fossil
hunts provide an enjoyable and educational experience for all. To find
out more
CLICK HERE

References: The Geology of Britain,
P.Toghill; British Regional Geology, The Midland Valley; en.wikipedia.org;
www.uni-muenster.de; A Dynamic Stratigraphy of the British Isles, R.Anderton
and co.

Picture credits: Mackenzie delta by Lois Brown at
www.shetravelsphotography.com; dragonfly by 'pjayres' at www.flickr.com;
jungle palm by 'janeandpoppy' at www.flickr.com; Arthropleura from
www.palaeos.com.

Safety notice: Fossil hunting can at times pose a risk to personal safety, in particular within environments close to the coast, cliffs
or in quarries and when using the tools and equipment illustrated. Discovering Fossils provides a free resource to inform you about
this fascinating subject and does not accept any liability for decisions made using this information. We recommend all individuals
abide by the fossil hunting guidelines available by clicking on the icon at the top of the page.